Differences between family practices in the associations of patient characteristics with health care experiences.

When comparing health care providers, patient experience data are usually adjusted for case-mix associations to ensure fair comparisons. Previous studies in the United States showed that case-mix associations sometimes vary across health care providers. Such variation could indicate differential provider behavior for patient subgroups, in which case current adjustment techniques might be inappropriate. To see whether this variation is also apparent in a health care system different from the U.S. system, the authors analyzed Dutch patients' experiences with family practice care. Using multilevel random slope models, the associations between age, general health status, mental health status, education, sex, and ethnicity on one hand and reported experiences on the other hand were assessed across family practices. The authors found only five significant variances between case-mix coefficients, all for outcomes related to health care professionals' conduct. These findings correspond to previous U.S. findings, suggesting that the case-mix variations reported here and previously constitute a rather robust phenomenon.